autoBreakConductors: share conductors_handled/used_terminals across batch

When multiple elements are pasted or moved in one batch, each call to
autoBreakConductors() now receives the shared state from the previous
call.  This prevents two elements in the same batch from independently
claiming the same conductor, which would result in a double-delete on
redo().

Requested by ispyisail in PR review.

sources/autobreakconductor.h

@@ -19,10 +19,12 @@
 #define AUTOBREAKCONDUCTOR_H
 
 #include <QSet>
+#include <QList>
 
 class Diagram;
 class Element;
 class Terminal;
+class Conductor;
 class QUndoCommand;
 
 /**
@@ -32,17 +34,24 @@ class QUndoCommand;
 	element's terminal.  Broken conductors from the same circuit (sharing the
 	same far-end endpoint) are broken together; independent crossing
 	conductors are left untouched.
-	@param diagram  the diagram containing the conductors
-	@param element  the element whose terminals trigger breaks
-	@param parent   undo command under which break/reconnect sub-commands
-	                are created (may be nullptr, in which case no undo is
-	                recorded)
+	@param diagram            the diagram containing the conductors
+	@param element            the element whose terminals trigger breaks
+	@param parent             undo command under which break/reconnect
+	                          sub-commands are created
+	@param conductors_handled shared list of conductors already claimed by
+	                          a previous call in the same batch (prevents
+	                          double-processing when multiple elements are
+	                          broken in one pass)
+	@param used_terminals     shared set of terminals already used as
+	                          connect_to or other_terminal in the same batch
 	@return set of terminals that were connected to a broken conductor's
 	        far-end (useful for preventing duplicate auto-connect)
 */
 QSet<Terminal *> autoBreakConductors(
 	Diagram *diagram,
 	Element *element,
-	QUndoCommand *parent);
+	QUndoCommand *parent,
+	QList<Conductor *> &conductors_handled,
+	QSet<Terminal *> &used_terminals);
 
 #endif // AUTOBREAKCONDUCTOR_H